Review of signal processing techniques for time-varying harmonic decomposition

The trend towards the implementation of Smart Grids results in a higher complexity of power signals and their voltage quality implication. Thus the need for more advanced signal processing techniques is required. A number of techniques have been recently developed and proposed in order to analyze the new environment and phenomena. Among these techniques this paper discusses different time-frequency methods used in power systems disturbance analysis. Filter Banks, Sliding-Window Recursive-DFT (SWR-DFT) and Wavelet Packet Transform (WPT) are compared. The methods are discussed based on their advantages and disadvantages. Signals with harmonic and inter-harmonics distortion are used in order to compare performance of the methods related to fundamental frequency variations, fast magnitude oscillations and inter-harmonics. The results presented in this work should assist quality expert to select the appropriate method according to application.